Latin word iter comes from Proto-Indo-European *ey, and later Proto-Indo-European *h₁ítr̥ (Way, course.)

Detailed word origin of iter

Dictionary entry	Language	Definition
*ey	Proto-Indo-European (ine-pro)
*h₁ítr̥	Proto-Indo-European (ine-pro)	Way, course.
iter	Latin (lat)	(Medieval, law) A court circuit.. (Medieval, medical) A passage.. A course.. A journey.. A march.. A path; a road.. A route, whether.